Thermo-electric element.



' UNITED stares.

llatented. January 31, 19Q5.

PATENT Erica;

ALBERT L. MARSH, OF LAKE BLUFF, ILLINOIS, AssIGNoR TO WILLiAM.

A. SPINKS & COMPANY, OF oHicAeoiLLmoIs, A? FIRM.

THERMOEELECTREC Emmett i SPECIFICATION forming part of Letters Patent No. 781,289, dated J anuary 31 1905,"

Application fi1ed0otobei-I8,1904. Serial No. 228343 I To all whmn, it may concern: Be it known that I, ALBERT L. MARSH, 'acitizen of the United States, residing at Lake Bluff,

in the county of Lake and State of Illinois,have

invented a new and useful Thermo-Electric Element, of which the following is a specification.

My object is to provide an improved thermoelectric element which may be employed with another element to produce a thermo-electric couple having a particularly high meltingpoint.

I have discovered that the metal molybdenum, which has a very high melting-point,

may, particularly when alloyed with nickel, be employed as a thermo-electric element electronegative to a nickel-copper element. Such a negative element renders it possible to construct thermo-electric couples'of comparacarried on with a view to discovering a readily-available metal having a melting-point ex' ceeding, more especially, that of pure copper and which, either alone or when alloyed with other metal or metals, would be either electropositive or clectronegative to another highlyrefractory metal or alloy with which it could be joined in a thermo-electric couple and possess the characteristics above set forth as my object, as well as comparatively great strength and durability. I have found that molybdenum may when alloyed with nickel be formed into a thermo-electric element strongly electronegative to an element formed of an alloy of nickel and copper.

and positive elements have melting-points much higher than that of pure copper andv may besubjected without danger to intense heat, thereby establishing adifl'erence of elec- Both the'saidnegative trio potential at least equal toany othdriprac-j tical couple ofwhioh I am aware withoutthe drawbacks incident tosaid other couples. 5-0

In constructing a thermo-electricbattery,

for example, I prefer toprovide the positive element of each couple of an alloy of nickel (about thirty-five per cent. and copper, (about sixty-five per cent.) This element has-a fus. 5 5 ing-point much above 1,050 centigrade, the approximate fusingpoint of pure copper. I r form the negative element of an alloy of molybdenum (about fifteen per cent.) and niclgel', 1

(about eighty-five per cent.) Bars of the al 66 I loys named may be readily welded together at their ends to form thermo-electric couple-s.

The main advantages of a thermo-electric couple constructed of the elements described lie, first, in the great strength and durability 5 of the'coiiple; second, in the fact that as it may be subjected -to heat 01' reat intensity care in thematter of heat regu-iation is unnec-' essary; third,- in the fact that th elements maybe as thin as desired for rapid heat r'a- 7 diation at the ends farthest from their heated joints, and, fourth, in the fact that the elements maybe welded together to'produce a joint equally heat-resistant with the body portions of the elements. I In the accompanying drawing I show for purposes of illustration a thermopileof one desirable form in cross-section with -thermo 1 electric couples connected in'seriestd forni an eiiicient thermo-electric generator. i A is a combustion-chamber surrounded by a wall B of highly-refractory material, such' as tire-clay,- asbestos, or the like. (JO indicatethermo-electric couples, each comprising a positive element in the form of 5 a strip a of the nickel-copper alloy mentioned I and a negative element in the form ofa strip 6 of the molybdenum-nickel alloy mentioned. The elements of "each couple are preferably electrically welded together to form a joint 0, '9 and they pas through the wallBto-extend at their joints in the combustion charfibr A2 Y The thermo-electric couplesare connected ina common manner by means of;strips d,wl5ii5ilf 1.;

' have theusual terminals, one of which would tensity from afBunse ends and a coolingaction at their outer ends,

i. may be air-cooled, or they may be subjec. ad to greatest efficiency for an indefinite time Withtive element.

ma be of co er, and the thermoaile ma. W hat I claim as new and 'desire to secure 5 l l a i by Letters Patent, is"

1. A thermoelectric couple, one clement or which is formed in Whole or in part of molyhl denum.

E3. A thermo-electric couple, one'clei iento1 which consists of an alloy of molybdemun and another metal.

3. A thermoelectric couple, one element of be positive and the other negative. The couples C may be sutiected in the chamber A,

for example, to a irect blast of great in burner. The couples 5 will generate\tlllleelectric current of an efH- ciency at least equal to that which maybe Q generated by the most efficient couples hitherto. constructed and of whiclir l am aware, and they may be subjected to a heat at their inner nickel.

- 4. A thermo-electric couple, one element of which consists of an alloy of molybdenum and nickel in substantially the proportions set forth.

5. A thernio-clcctric couple, one element of which consists of an alloy of molybdenum and which maintains them l at approximately the out affecting their durability to'any mate. i extent. The outer end portions'of the coup es water-cooling or other artificial refrig err on. I'have obtained the best results by employl which nickel forms a part.

ing'la molybdenum -nickel alloy in substan- 6. A thermo-electric couple, one

tially the proportions named forthe negative I element and a nickel-copper alloy in'substan nickel and the other element of an alloy of tially the proportions named for the posi-" nickel and copper,

My invention, however, is notl element of 'AL BERT L. MARSH;

in presence of WALTER N. W NBERG, I E. P. RICH;

in its broad sense to be limited by'this state- I ment, as the main point of my invention lies in the discovery of the use of molybdenum as an element in a theremo-electric couple.

which consists of an alloyot' molybdenum and.

nickel and the other el'ement ot' an alloy of.

which consists of an alloy of molybdenum and I 

